Keyboard



FIG. 1 is a front, perspective view of a first embodiment thereof;

FIG. 2 is a bottom view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a front view thereof;

FIG. 7 is a rear view thereof; and,

FIG. 8 is a rear perspective view thereof.

The broken lines represent environmental subject matter that forms no part of the claimed design. 

The ornamental design for a keyboard, as shown and described. 